This carbon filter is for use with most NXT dehumidifiers*. It sits behind the pre-filter on your Watchdog Crawl Space Dehumidifier. It is used as a replacement filter for the standard MERV-10 filter that is included with your dehumidifier. A carbon filter is effectively removes dirt and dust particles as well as odors from the air. It is recommended that the filter be changed about once a year. It is not washable.
The N-203 comes in a 3 pack.